Does Yellow OUT work

[martyhammer]

Thanks for such a thorough reply, Richard. Due to imminent storm, and I need to leave town again in a couple of days, I went ahead and started the "treatment"....I'm finding that even though I've used a lot of chlorine (Cal Hypo) for shock, I am not getting a reading above just 2-3 PPM (normally, the amount of Cal Hypo I put in would give me 15 PPM)! I even threw in some Lithium Hypo! I did raise the PH first to 8.0 before adding the Yellow Out and the water is indeed a bit cloudy (from the Soda Ash). Would the Yellow Out (or the higher PH) cause a Taylor chlorine titration test to give false readings? (I would think not). I need to wait now til the storm is over (Hanna passing through later today), and see what the readings are tomorrow (e.g., FC and CC) to see what I minimally need to do before I leave on Monday (I *know* I need to vacuum and backwash before I leave). Do you suggest using acid to bring PH back down quickly from 8.0 or just let it drift...the groundwater Ph is 7.6, so I would expect the pool to get there without too much time (especially if I get a lot of rain today...they don't call it acid rain for nothin'!).

Thanks again!
-Marty

[chem geek]

The Yellow Out is using up the chlorine so that's why you get a low FC reading -- that is expected. I would also expect that your Combined Chlorine (CC) reading could be high during this period until you add more chlorine (which will get rid of the CC), but you don't do this right away..

Since you've used this product, I would suggest following its directions which means after the Yellow Out and chlorine addition, wait 24 hours, then add more chlorine again to 10 ppm. That should get rid of any CC.

At that point, you should be back to normal in the pool and can use Ben's chart as a guide and not let the FC get below 3 ppm FC with your 50 ppm CYA.